Acquisition and assimilation of nitrogen as peptide-bound and D-enantiomers of amino acids by wheat.
Acquisition and assimilation of nitrogen as peptide-bound and D-enantiomers of amino acids by wheat.
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DOI：
10.1371/journal.pone.0019220
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发表时间：
2011-04-26
期刊：
影响因子：
3.7
通讯作者：
Jones DL
中科院分区：
文献类型：
--
作者：
Hill PW;Quilliam RS;DeLuca TH;Farrar J;Farrell M;Roberts P;Newsham KK;Hopkins DW;Bardgett RD;Jones DL
氮是许多陆地生态系统初级生产力的关键调节因子。历史上，只有无机氮（NH 4+和NO 3-）和L-氨基酸被认为是重要的陆生植物的氮营养。然而，氨基酸也存在于土壤中的小肽和D-对映体形式。我们比较了吸收和同化的N作为游离氨基酸和短同肽的L-和D-对映体形式。小麦（Triticum aestivum L.）将植物暴露于含有14 C标记的L-丙氨酸、D-丙氨酸、L-三丙氨酸或D-三丙氨酸的溶液中，其浓度可能在土壤溶液中发现（10 μM）。在5小时内，植物吸收L-丙氨酸、D-丙氨酸和L-三丙氨酸的速率分别为0.9±0.3、0.3±0.06和0.3±0.04 µmol g−1根DW h−1。L-三丙氨酸和L-丙氨酸的吸氮速率相同。植物失去了约。60%的氨基酸C采取呼吸，无论对映体形式，但更多（约80%）的L-三丙氨酸C比氨基酸C被呼吸。当供应的混合N形式的溶液中，N的吸收作为D-丙氨酸是约。5倍快于NO3 -，但慢于L-丙氨酸，L-三丙氨酸和NH 4+。植物吸收D-三丙氨酸的能力有限（0.04±0.03 µmol g−1根DW h−1），但似乎不能代谢它。我们得出结论，小麦能够利用L-肽和D-氨基酸N，其速率与公认重要的N形式（即L-氨基酸和无机N）的速率相当。这是真实的，即使溶质在现实的土壤浓度和其他形式的N供应。我们建议，它可能是必要的，以重新考虑哪些形式的土壤氮是重要的陆地氮循环。
Nitrogen is a key regulator of primary productivity in many terrestrial ecosystems. Historically, only inorganic N (NH4 + and NO3 -) and L-amino acids have been considered to be important to the N nutrition of terrestrial plants. However, amino acids are also present in soil as small peptides and in D-enantiomeric form. We compared the uptake and assimilation of N as free amino acid and short homopeptide in both L- and D-enantiomeric forms. Sterile roots of wheat (Triticum aestivum L.) plants were exposed to solutions containing either 14C-labelled L-alanine, D-alanine, L-trialanine or D-trialanine at a concentration likely to be found in soil solution (10 µM). Over 5 h, plants took up L-alanine, D-alanine and L-trialanine at rates of 0.9±0.3, 0.3±0.06 and 0.3±0.04 µmol g−1 root DW h−1, respectively. The rate of N uptake as L-trialanine was the same as that as L-alanine. Plants lost ca.60% of amino acid C taken up in respiration, regardless of the enantiomeric form, but more (ca.80%) of the L-trialanine C than amino acid C was respired. When supplied in solutions of mixed N form, N uptake as D-alanine was ca.5-fold faster than as NO3 -, but slower than as L-alanine, L-trialanine and NH4 +. Plants showed a limited capacity to take up D-trialanine (0.04±0.03 µmol g−1 root DW h−1), but did not appear to be able to metabolise it. We conclude that wheat is able to utilise L-peptide and D-amino acid N at rates comparable to those of N forms of acknowledged importance, namely L-amino acids and inorganic N. This is true even when solutes are supplied at realistic soil concentrations and when other forms of N are available. We suggest that it may be necessary to reconsider which forms of soil N are important in the terrestrial N cycle.
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影响因子：
6.9
作者：
Paungfoo-Lonhienne C;Schenk PM;Lonhienne TG;Brackin R;Meier S;Rentsch D;Schmidt S
通讯作者：
Schmidt S
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Soda, Kenji
影响因子：
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作者：
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通讯作者：
Farrar, JF
影响因子：
9.7
作者：
O'Dowd, RW;Parsons, R;Hopkins, DW
通讯作者：
Hopkins, DW
影响因子：
9.7
作者：
Hill, Paul W.;Farrar, John F.;Jones, David L.
通讯作者：
Jones, David L.